Changing the oil in a car or other engine typically involves emptying a number of one quart plastic oil containers into the engine crankcase. Since an average car accepts on the average of four to six quarts, and airplanes can accept even more, a number of the containers are used. Oil is a viscous fluid tending to flow slowly, requiring a long period of time to drain the last amounts of oil from the walls of the inverted container. Most oil changes are viewed as short term activities and people are reluctant to wait any appreciable time while the container relinquishes its last drop. Nevertheless, many mechanics shops are aware that by hurriedly draining the bulk of the oil and disposing of the container wastes oil. The amount of wasted oil per container is small, but in a facility that uses large amounts of oil, such as a car repair shop or an airplane maintenance hanger, the accumulated amount of wasted oil can be appreciable. It would be desirable to have a device for recovering this otherwise wasted oil.
Prior art devices exist for draining and collecting oil from a plurality of oil cans. Many of these devices are designed for use with the old style cylindrically shaped puncture cans, which are obsolete in most areas. Newer containers are more efficiently designed, with squared sides and necks with screw caps for easier use.
One of the problems with prior art devices is that they fail to adequately prevent dirt and other contamination from entering the funnel or drainage system and mixing with the oil. Dirt of other particulate matter or diluents in oil can substantially reduce its effectiveness, or even cause damage to the engine. U.S. Pat. No. 4,832,095, issued to Bonnell, discloses a device for collecting viscous fluids having a two-by-three array of openings for draining cylindrical or box shaped oil containers. Bonnell has a cover that protects the entire funnel and all the openings at once. However, it is more likely that the device will remain uncovered while in use, and, if only one or less than all of the openings are in use, dirt can still enter the funnel. Previous devices have attempted to address the contamination issue, but have failed to provide a convenient closure means that would allow some of the openings to be in use while others to be capped off.